Download or read book Modeling the Structural Response from a Propagating High Explosive Using Smooth Particle Hydrodynamics written by and published by . This book was released on 2012 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report primarily concerns the use of two massively parallel finite element codes originally written and maintained at Lawrence Livermore National Laboratory. ALE3D is an explicit hydrodynamics code commonly employed to simulate wave propagation from high energy scenarios and the resulting interaction with nearby structures. This coupled response ensures that a structure is accurately applied with a blast loading varying both in space and time. Figure 1 illustrates the radial outward propagation of a pressure wave due to a center detonated spherical explosive originating from the lower left. The radial symmetry seen in this scenario is lost when instead a cylindrocal charge is detonated. Figure 2 indicates that a stronger, faster traveling pressure wave occurs in the direction of the normal axis to the cylinder. The ALE3D name is derived because of the use of arbitrary-Lagrange-Eulerian elements in which the mesh is allowed to advect; a process through which the mesh is modified to alleviate tanlging and general mesh distortion often cuased by high energy scenarios. The counterpart to an advecting element is a Lagrange element, whose mesh moves with the material. Ideally all structural components are kept Lagrange as long as possible to preserve accuracy of material variables and minimize advection related errors. Advection leads to mixed zoning, so using structural Lagrange elements also improves the visualization when post processing the results. A simplified representation of the advection process is shown in Figure 3. First the mesh is distorted due to material motion during the Lagrange step. The mesh is then shifted to an idealized and less distorted state to prevent irregular zones caused by the Lagrange motion. Lastly, the state variables are remapped to the elements of the newly constructed mesh. Note that Figure 3 represents a purely Eulerian mesh relaxation because the mesh is relocated back to the pre-Lagrange position. This is the case when the material flows through a still mesh. This is not typically done in an ALE3D analysis, especially if Lagrange elements exist. Deforming Lagrange elements would certainly tangle with a Eulerian mesh eventually. The best method in this case is to have an advecting mesh positioned as some relaxed version of the pre and post Lagrange step; this gives the best opportunity of modeling a high energy event with a combination of Lagrange and ALE elements. Dyne3D is another explicit dynamic analysis code, ParaDyn being the parallel version. ParaDyn is used for predicting the transient response of three dimensional structures using Lagrangian solid mechanics. Large deformation and mesh tangling is often resolved through the use of an element deletion scheme. This is useful to accommodate component failure, but if it is done purely as a means to preserve a useful mesh it can lead to problems because it does not maintain continuity of the material bulk response. Whatever medium exists between structural components is typically not modeled in ParaDyn. Instead, a structure either has a known loading profile applied or given initial conditions. The many included contact algorithms can calculate the loading response of materials if and when they collide. A recent implementation of an SPH module in which failed or deleted material nodes are converted to independent particles is currently being utilized for a variety of spall related problems and high velocity impact scenarios. Figure 4 shows an example of a projectile, given an initial velocity, and how it fails the first plate which generates SPH particles which then interact with and damage the second plate.
Download or read book Hydrodynamic Modeling of Detonations for Structural Design of Containment Vessels written by and published by . This book was released on 2005 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Los Alamos National Laboratory (LANL), under the auspices of the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA), has been conducting confined high explosion experiments utilizing large, spherical, steel pressure vessels to contain the reaction products and hazardous materials from high-explosive (HE) events. Structural design of these spherical vessels was originally accomplished by maintaining that the vessel's kinetic energy, developed from the detonation impulse loading, be equilibrated by the elastic strain energy inherent in the vessel. In some cases, the vessel is designed for one-time use only, efficiently utilizing the significant plastic energy absorption capability of ductile vessel materials. Alternatively, the vessel can be designed for multiple use, in which case the material response is restricted to the elastic range. Within the last decade, designs have been accomplished utilizing sophisticated and advanced 3D computer codes that address both the detonation hydrodynamics and the vessel's highly nonlinear structural dynamic response. This paper describes the hydrodynamic modeling of HE reaction products phase, which produces transient pressures resulting in an impulsive load on the vessel shell. Modeling is accomplished through either (a) empirical/analytical methods utilizing a vast experimental database developed primarily for the Department of Defense (DoD) or (b) through application of numerical hydrodynamics codes, such as the Sandia National Laboratories (SNL) shock-wave physics code, CTH, which accurately model the thermochemistry and thermophysics of a detonation. It should be noted that this paper only addresses blast load prediction using the methods stated and does not include an assessment of structural response methods.
Download or read book Hydrodynamics of Explosion written by V. K. Kedrinskiĭ and published by Springer Science & Business Media. This book was released on 2005-07-22 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: PRELIMINARY TEXT: The book includes results of experimental studies and mathematical models of wide class of nonstationary processes developing in liquid under pulse (explosive) loading. The author addresses engineers and scientists from scientific computation. Experimental results on structure and parameters of wave fields generated by explosions of cord and spiral charges, description of formation mechanisms of high speed cumulative flows at underwater explosions near free surface as well as studies on dynamics of spherical, cylindrical and ring cavities are presented. The features of shock wave transformation in bubbly liquids, their amplification as a result of collision and focusing, bubbly detonation wave formation in reactive bubbly liquids are in detail analyzed. The results of studies of real liquid microstructure as two-phase medium, bubbly cavitation development, rarefaction waves in real liquids, notion of their strength, relaxation of tensile stresses and process of liquid fructure under pulse (explosive) loading are discussed in detail.
Download or read book Smoothed Particle Hydrodynamics written by Gui-Rong Liu and published by World Scientific. This book was released on 2003 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first-ever book on smoothed particle hydrodynamics (SPH) and its variations, covering the theoretical background, numerical techniques, code implementation issues, and many novel and interesting applications. It contains many appealing and practical examples, including free surface flows, high explosive detonation and explosion, underwater explosion and water mitigation of explosive shocks, high velocity impact and penetration, and multiple scale simulations coupled with the molecular dynamics method. An SPH source code is provided and coupling of SPH and molecular dynamics is discussed for multiscale simulation, making this a friendly book for readers and SPH users.
Download or read book Coupled Explosive written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation of the effects of explosives on structures is a challenge because the explosive response can best be simulated using Eulerian computational techniques and structural behavior is best modeled using Lagrangian methods. Due to the different methodology of the two computational techniques and code architecture requirements, they are usually implemented in different computer programs. Explosive and structure modeling in two different codes make it difficult or next to impossible to do coupled explosive/structure interaction simulations. Sandia National Laboratories has developed two techniques for solving this problem. The first is called Smoothed Particle Hydrodynamics (SPH), a relatively new gridless method comparable to Eulerian, that is especially suited for treating liquids and gases such as those produced by an explosive. The SPH capability has been fully implemented into the transient dynamics finite element (Lagrangian) codes PRONTO-2D and -3D. A PRONTO-3D/SPH simulation of the effect of a blast on a protective-wall barrier is presented in this paper. The second technique employed at Sandia uses a new code called Zapotec that combines the 3-D Eulerian code CTH and the Lagrangian code PRONTO-3D with minimal changes to either code. CTH and PRONTO-3D are currently executing on the Sandia Terraflops machine (9000 Pentium Pro processors). Eulerian simulations with 100 million cells have been completed on the current configuration of the machine (4500 Pentium Pro processors). The CTH and PRONTO-3D combination will soon be executing in a coupled fashion on this machine.
Download or read book Design Against Blast written by S. Syngellakis and published by WIT Press. This book was released on 2013 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Terrorist attacks and other destructive incidents caused by explosives have, in recent years, prompted considerable research and development into the protection of structures against blast loads. For this objective to be achieved, experiments have been performed and theoretical studies carried out to improve our assessments of the intensity as well as the space-time distribution of the resulting blast pressure on the one hand and the consequences of an explosion to the exposed environment on the other.This book aims to enhance awareness on and understanding of these topical issues through a collection of relevant, Transactions of the Wessex Institute of Technology articles written by experts in the field. The book starts with an overview of key physics-based algorithms for blast and fragment environment characterisation, structural response analyses and structural assessments with reference to a terrorist attack in an urban environment and the management of its inherent uncertainties.A subsequent group of articles is concerned with the accurate definition of blast pressure, which is an essential prerequisite to the reliable assessment of the consequences of an explosion. Other papers are concerned with alternative methods for the determination of blast pressure, based on experimental measurements or neural networks. A final group of articles reports investigations on predicting the response of specific structural entities and their contents.The book concludes with studies on the effectiveness of steel-reinforced polymer in improving the performance of reinforced concrete columns and the failure mechanisms of seamless steel pipes used in nuclear industry.
Download or read book Numerical Modeling of Explosives and Propellants Second Edition written by Charles L. Mader and published by CRC Press. This book was released on 1997-08-29 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charles Mader, a leading scientist who conducted theoretical research at Los Alamos National Laboratory for more than 30 years, sets a new standard with this reference on numerical modeling of explosives and propellants. This book updates and expands the information presented in the author's landmark work, Numerical Modeling of Detonations, published in 1979 and still in use today. Numerical Modeling of Explosives and Propellants incorporates the considerable changes the personal computer has brought to numerical modeling since the first book was published, and includes new three-dimensional modeling techniques and new information on propellant performance and vulnerability. Both an introduction to the physics and chemistry of explosives and propellants and a guide to numerical modeling of detonation and reactive fluid dynamics, Numerical Modeling of Explosives and Propellants offers scientists and engineers a complete picture of the current state of explosive and propellant technology and numerical modeling. The book is richly illustrated with figures that support the concepts, and filled with tables for quick access to precise data. The accompanying CD-ROM contains computer codes that are the national standard by which modeling is evaluated. Dynamic material properties data files and animation files are also included. There is no other book available today that offers this vital information.
Download or read book On the Feasibility of Using Smoothed Particle Hydrodynamics for Underwater Explosion Calculations written by and published by . This book was released on 1995 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: SPH (Smoothed Particle Hydrodynamics) is a gridless Lagrangian technique which is appealing as a possible alternative to numerical techniques currently used to analyze high deformation impulsive loading events. In the present study, the SPH algorithm has been subjected to detailed testing and analysis to determine the feasibility of using PRONTO/SPH for the analysis of various types of underwater explosion problems involving fluid-structure and shock-structure interactions. Of particular interest are effects of bubble formation and collapse and the permanent deformation of thin walled structures due to these loadings. These are exceptionally difficult problems to model. Past attempts with various types of codes have not been satisfactory. Coupling SPH into the finite element code PRONTO represents a new approach to the problem. Results show that the method is well-suited for transmission of loads from underwater explosions to nearby structures, but the calculation of late time effects due to acceleration of gravity and bubble buoyancy will require additional development, and possibly coupling with implicit or incompressible methods.
Download or read book Blast Mitigation written by Arun Shukla and published by Springer Science & Business Media. This book was released on 2013-07-06 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blast Mitigation: Experimental and Numerical Studies covers both experimental and numerical aspects of material and structural response to dynamic blast loads and its mitigation. The authors present the most up-to-date understanding from laboratory studies and computational analysis for researchers working in the field of blast loadings and their effect on material and structural failure, develop designs for lighter and highly efficient structural members for blast energy absorption, discuss vulnerability of underground structures, present methods for dampening blast overpressures, discuss structural post blast collapse and give attention to underwater explosion and implosion effects on submerged infrastructure and mitigation measures for this environment.
Download or read book Soft Target Protection written by Ladislav Hofreiter and published by Springer Nature. This book was released on 2020-03-03 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume includes articles presented during the Advanced Research Workshop on Soft Target Protection. The book presents important topics related to the protection of vulnerable objects and spaces, called Soft Targets. The chapters published in this book are thematically assigned to the blocks as follows: Theoretical aspect of soft target protection; Blast resistance of soft targets; Counter terrorism; Technical and technological solutions for soft target protection; Scheme and organizational measures; Blast protection and Forces for soft target protection. In this book, the reader will find a wealth of information about the theoretical background for designing protection of soft targets, as well as the specifics of protecting objects in armed conflict areas. New methods and procedures applicable to the soft target protection are described.
Download or read book Modeling Coupled Blast structure Interaction with Zapotec Benchmark Calculations for the Conventional Weapon Effects Backfill CONWEB Tests written by Gregory Carl Bessette and published by . This book was released on 2004 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling the response of buried reinforced concrete structures subjected to close-in detonations of conventional high explosives poses a challenge for a number of reasons. Foremost, there is the potential for coupled interaction between the blast and structure. Coupling enters the problem whenever the structure deformation affects the stress state in the neighboring soil, which in turn, affects the loading on the structure. Additional challenges for numerical modeling include handling disparate degrees of material deformation encountered in the structure and surrounding soil, modeling the structure details (e.g., modeling the concrete with embedded reinforcement, jointed connections, etc.), providing adequate mesh resolution, and characterizing the soil response under blast loading. There are numerous numerical approaches for modeling this class of problem (e.g., coupled finite element/smooth particle hydrodynamics, arbitrary Lagrange-Eulerian methods, etc.). The focus of this work will be the use of a coupled Euler-Lagrange (CEL) solution approach. In particular, the development and application of a CEL capability within the Zapotec code is described. Zapotec links two production codes, CTH and Pronto3D. CTH, an Eulerian shock physics code, performs the Eulerian portion of the calculation, while Pronto3D, an explicit finite element code, performs the Lagrangian portion. The two codes are run concurrently with the appropriate portions of a problem solved on their respective computational domains. Zapotec handles the coupling between the two domains. The application of the CEL methodology within Zapotec for modeling coupled blast/structure interaction will be investigated by a series of benchmark calculations. These benchmarks rely on data from the Conventional Weapons Effects Backfill (CONWEB) test series. In these tests, a 15.4-lb pipe-encased C-4 charge was detonated in soil at a 5-foot standoff from a buried test structure. The test structure was composed of a reinforced concrete slab bolted to a reaction structure. Both the slab thickness and soil media were varied in the test series. The wealth of data obtained from these tests along with the variations in experimental setups provide ample opportunity to assess the robustness of the Zapotec CEL methodology.
Download or read book The Finite Volume Method in Computational Fluid Dynamics written by F. Moukalled and published by Springer. This book was released on 2015-08-13 with total page 799 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook explores both the theoretical foundation of the Finite Volume Method (FVM) and its applications in Computational Fluid Dynamics (CFD). Readers will discover a thorough explanation of the FVM numerics and algorithms used for the simulation of incompressible and compressible fluid flows, along with a detailed examination of the components needed for the development of a collocated unstructured pressure-based CFD solver. Two particular CFD codes are explored. The first is uFVM, a three-dimensional unstructured pressure-based finite volume academic CFD code, implemented within Matlab. The second is OpenFOAM®, an open source framework used in the development of a range of CFD programs for the simulation of industrial scale flow problems. With over 220 figures, numerous examples and more than one hundred exercise on FVM numerics, programming, and applications, this textbook is suitable for use in an introductory course on the FVM, in an advanced course on numerics, and as a reference for CFD programmers and researchers.
Download or read book Marine Structures written by Erkan Oterkus and published by MDPI. This book was released on 2020-01-31 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural mechanics is an important field of engineering. The main goal of structural mechanics is to ensure that structures are safe and durable so that catastrophic situations can be prevented, which can otherwise cause loss of life, environmental pollution and financial losses. Depending on the uses of the structure and the conditions that the structure is subjected to, special treatment may be required for the analysis. Specifically, marine structures are subjected to harsh environmental conditions due to the marine environment, which can cause several different damage mechanisms including fatigue and corrosion. This book on “Marine structures” considers a wide range of areas related to marine structures and provides a compilation of numerical and experimental studies related to “Marine structures” research.
Download or read book Progress in Model Development to Quantify High Explosive Violent Response HEVR to Mechancial Insult written by and published by . This book was released on 2008 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid release of chemical energy has found application for industrial and military purposes since the invention of gunpowder. Black powder, smokeless powder of various compositions, and pyrotechnics all exhibit the rapid release of energy without detonation when they are being used as designed. The rapidity of energy release for these materials is controlled by adjustments to the particle surface area (propellant grain configuration or powder particle size) in conjunction with the measured pressure-dependent burning rate, which is very subsonic. In this way a manufacturing process can be used to engineer the desired violence of the explosion. Detonations in molecular explosives, in contrast, propagate with a supersonic velocity that depends on the loading density, but is independent of the surface area. In ideal detonations, the reaction is complete within a small distance of the propagating shock front. Non-ideal detonations in molecular and composite explosives proceed with a slower velocity, and the reaction may continue well behind the shock front. We are developing models to describe the circumstances when molecular and composite explosives undergo a rapid release of energy without detonating. The models also apply to the behavior of rocket propellants subject to mechanical insult, whether for accidents (Hazards) or the suite of standardized tests used to assess whether the system can be designated an Insensitive Munition (IM). In the application described here, we are studying an HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane) explosive developed in the UK, which is 91% by weight HMX and 9% binder-plasticizer. Most explosives and propellants, when subjected to a mechanical insult, drop or impact that is well below the threshold for detonation have been observed to react violently. This behavior is known as High Explosive Violent Reaction (HEVR). The basis of our model is the observation that the mechanical insult produces damage in a volume of the explosive near the trajectory of the impactor. The damage is manifest as surface area through the creation of cracks and fragments, and also as porosity through the separation of crack faces and isolation of the fragments. Open porosity permits a flame to spread easily and so ignite the surface area that was created. The surface area itself leads to in increase in the mass-burning rate. As the kinetic energy and power of the insult increases, the degree of damage and the volume of damage both increase. Upon a localized ignition, the flame spreads to envelop the damaged volume, and the pressure rises at an accelerated rate until neither mechanical strength nor inertial confinement can successfully contain the pressure. The confining structure begins to expand. This reduces the pressure and may even extinguish the flame. Both the mass of explosive involved and the rate at which the gas is produced contribute to each of several different measures of violence. Such measures include damage to the confinement, the velocity and fragment size distributions from what was the confinement, and air blast. Figure 1 illustrates the interaction of the various phenomena described above. Our model comprises several interacting elements. The production of damage, the ignition criterion, the mass rate of burning (reaction rate), the equations of state and constitutive models of the solid explosive reactant (unburned) and gas products, flame propagation in damaged reactant, and the progressive failure of the confinement are all elements of the model. The model is intended for implementation in a general-purpose simulation program (hydrocode) that solves the partial differential equations for the conservation of mass, momentum, and energy in conjunction with equations of state and strength.
Download or read book Smoothed Particle Hydrodynamics and Its Applications in Simulating High Explosive Explosions written by Moubin Liu and published by . This book was released on 2003 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Building Information Modeling written by Nawari O. Nawari and published by CRC Press. This book was released on 2015-05-01 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: BIM for Structural Engineering and Architecture Building Information Modeling: Framework for Structural Design outlines one of the most promising new developments in architecture, engineering, and construction (AEC). Building information modeling (BIM) is an information management and analysis technology that is changing the role of computation in the architectural and engineering industries. The innovative process constructs a database assembling all of the objects needed to build a specific structure. Instead of using a computer to produce a series of drawings that together describe the building, BIM creates a single illustration representing the building as a whole. This book highlights the BIM technology and explains how it is redefining the structural analysis and design of building structures. BIM as a Framework Enabler This book introduces a new framework—the structure and architecture synergy framework (SAS framework)—that helps develop and enhance the understanding of the fundamental principles of architectural analysis using BIM tools. Based upon three main components: the structural melody, structural poetry, and structural analysis, along with the BIM tools as the frame enabler, this new framework allows users to explore structural design as an art while also factoring in the principles of engineering. The framework stresses the influence structure can play in form generation and in defining spatial order and composition. By highlighting the interplay between architecture and structure, the book emphasizes the conceptual behaviors of structural systems and their aesthetic implications and enables readers to thoroughly understand the art and science of whole structural system concepts. Presents the use of BIM technology as part of a design process or framework that can lead to a more comprehensive, intelligent, and integrated building design Places special emphasis on the application of BIM technology for exploring the intimate relationship between structural engineering and architectural design Includes a discussion of current and emerging trends in structural engineering practice and the role of the structural engineer in building design using new BIM technologies Building Information Modeling: Framework for Structural Design provides a thorough understanding of architectural structures and introduces a new framework that revolutionizes the way building structures are designed and constructed.
Download or read book Simulations for the Explosion and Granular Impact Problems Using the SPH Method written by Jianyu Chen and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulations of explosions and granular impacts are challenging tasks to tackle using conventional mesh-based methods. In this thesis, a mesh-free technique called smoothed particle hydrodynamics (SPH) in conjunction with the Open-MP and CUDA parallel pro- gramming interfaces is introduced to tackle three-dimensional (3D) problems with large deformations. Chapter 1 gives an introduction of the SPH method and a literature review of the the- oretical improvement of SPH, landmine detonations, underwater explosions, and granular impacts. A research outline of the thesis is also presented at the end of this chapter. The basic ideas of the SPH method and some techniques which are relevant to improve the accuracy and stability of SPH, including the artificial viscosity, artificial stress, boundary implementation, neighboring particles search, and kernel gradient correction, are described in Chapter 2. In order to solve the governing equations, an elaboration of the constitutive models to update the stress tensor of soil and solid and the equation of states (EOSs) is given in Chapter 3. The simulations of the detonation and granular impact problems using the SPH method are thoroughly presented in chapters 4-7. In Chapter 4, in order to tackle 3D problems with large number of particles, the in-house SPH code is parallelized by the Open-MP programming interface. The parallel efficiency is tested by the 3D shaped charge detonation. The simulations of the 2D soil explosion and its effects on structures are investigated in Chapter 5. Based on the parallelization of the SPH code and the simulation of 2D soil explosion, the physical process of the 3D landmine detonation is studied further. The simulations of the 3D underwater explosion within cylindrical rigid and aluminium (Al) tubes including cavitation phenomenon are presented in Chapter 6. The simulations of the 3D granular impacts using GPU acceleration are presented in Chapter 7. The numerical results of SPH are compared against the experimental and other available numerical data, and it is shown that the SPH method is capable of predicting landmine detonations, underwater explosions, and granular impacts. The conclusions, novelties, and future plan of SPH research are summarized in Chapter 8.
